In order to connect an electric machine (such as an electric generator) to another electric component (such as a converter) usually shielded conductors are used.
FIG. 1a schematically shows an example of conductors 1 in a segregated arrangement; each conductor 1 comprises a conductive element 2 for example made of copper or aluminum, and a conductive shielding 3, for example made of aluminum. Between the conductive element 2 and the shielding 3 an air gap 4 is provided.
These conductors are widely used but in some applications could have some drawbacks.
In fact, the air gap 4 and shielding 3 sensibly increase the conductor diameter; thus when a lot of conductors must be provided to connect a lot of terminals together, the shielded conductors require a lot of space.
In addition, because of the air gap 4 and shielding 3, during operation cooling of these conductors is not efficient; in particular cooling requires powerful cooling systems to appropriately cool the conductive elements 2. These cooling systems consume a large power and thus affect efficiency.
In addition, these conductors can cause high losses in the shielding 3 for proximity effect.
FIG. 1b shows an example of conductors 1 in a non-segregated arrangement; in this case a number (usually three) of conductive elements 2 are all housed in the shielding 3.
This non-segregated arrangement of conductive elements 2 is more compact than the segregated arrangement, nevertheless since no insulation is provided between conductive elements 2, it can be used only when the differential voltage among the conductive elements 2 is low.